(NOT APPLICABLE)
This invention is related to an ink jet recording apparatus and method, and more particularly to an ink jet recording apparatus with a carriage lock mechanism and a method for controlling the same.
Typically an ink jet recording apparatus has a recording head which moves along a sheet of recording paper by means of a carriage, ejecting ink drops thus printing on the surface of the recording paper. Often times during printing, the carriage will be put into a waiting condition and be placed in a home position away from the printing area. While the carriage carrying the recording head is under a printing waiting condition, it moves to a predetermined home position, which is located off the recording area, and waits for a printing command at the home position.
Although the carriage driving mechanism applies a brake force to keep the carriage in its home position, exterior vibrations may move the carriage toward the recording area while the carriage is waiting in the home position. Furthermore, when electric power is turned off, the carriage may be able to freely move, and there is a risk that the carriage may move toward the recording area from the home position.
In order to prevent unwanted movement of the carriage, an ink jet recording apparatus is often provided with carriage lock mechanisms for mechanically fixing the carriage at the relevant home position. (For example, U.S. Pat. No. 4,695,851 and U.S. Pat. No. 4,739,847).
These conventional carriage locking mechanisms are constructed in such a way that each time the carriage returns to the home position the carriage is locked. Since the driving frequency of the carriage lock mechanism is high, there are associated problems with keeping the carriage locked. One such problem is that the components of the carriage lock mechanism rapidly deteriorate.
Another problem exists when printing should be restarted immediately after a previous printing is finished, requiring the carriage lock to be disengaged. The result is decreased responsiveness of the carriage when restarting printing.
It is desirable to have an ink jet recording apparatus which can prevent deterioration of the components caused by the carriage lock and decreased responsiveness when printing restarts, by avoiding unnecessary carriage lock actions.
In general, in one aspect, the invention features an ink jet recording apparatus which includes a recording head for ejecting ink liquid drops, a carriage for carrying the recording head and adapted to translate between a recording area and a home position, a carriage lock mechanism for locking the carriage at the home position, a carriage controller for translating the carriage to the home position, a timer for measuring a waiting time during which the carriage translated by the carriage drive control part is at the home position, a lock controller which allows the carriage lock mechanism and the carriage to be in a locked condition when the waiting time measured by the timer has reached or exceeded a reference time, and setting structure for setting or changing the reference time.
The carriage lock will not be effected even if the carriage has returned to the home position, unless the carriage is waiting at the home position for more time than a predetermined period. If a command for restarting printing is issued during the reference time, the carriage can be immediately moved to the recording area. If the carriage lock is set simultaneously when the carriage has returned to the home position, the driving frequency of the carriage lock mechanism is reduced, and the deterioration of the components of the carriage lock mechanism can be reduced. In addition, since frequency of disengaging the carriage lock mechanism is low, the responsiveness at the restart of printing will be improved.
The setting structure for setting or changing the reference time may change some values prepared in advance through a switch such as a dip switch. Moreover, it is also possible to prepare a memory for storing the reference time and a command interpreter for receiving and analyzing a command transmitted from a host device and to constitute the setting structure by the following firmware. More specifically, if the command analyzed by the command interpreter is the set command for setting or changing the value of the reference time, it is preferable that the value of the reference time should be stored in the memory or the value stored in the memory should be changed based on the set command.
If a time required for a period in which the carriage is returned to the home position and carriage locking is then carried out is too short, the number of the carriage locking operations is not decreased so that effects are not increased. To the contrary, if the waiting time is too long, a time required for a period in which the carriage is not locked is prolonged. Consequently, there is a higher possibility that the ink might leak due to oscillations or impacts. According to the invention, however, the provider or user of the recording apparatus can set and/or change, to an optimum time, the time required for the period in which the carriage is returned to the home position, and carriage locking is then carried out according to the configuration of use of the recording apparatus (for example, the frequency of printing).
Implementations may include a maintenance unit for restoring the relevant recording head by sucking ink from ink nozzles in the recording head and disposing it to the exterior, and head restoration requesting structure for issuing a head restoration request by the maintenance unit. It is preferable that the carriage lock is instantly engaged when the head restoration request is issued, regardless of the time during which the carriage is waiting at the home position, to prevent the ink from leaking out by movement of the carriage during suction of the ink.
Since the printing action will not start immediately after the electric source of the apparatus is switched on, the carriage can be locked by actuating the carriage lock mechanism, regardless of the above-described waiting time.
Implementations may also include a detector for detecting that the carriage has moved to the home position so as to start a measurement of the waiting time by means of the timer, by referring to results of detection by the detector as a trigger.
The method for controlling the ink jet recording device according to the present invention is also specified by the same technical matters as described above, and attains the same operational effects
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.